Control4 can work very well. As others have stated, dealers play a very important role. They can make or break a project. Dealers get paid based on both time and margin on hardware. If you live in a larger area get multiple bids. Look at both competence and price. Remember you are ultimately in charge of the scope & specs of the project.
The main selling points for C4 are UI ease of use, comprehensiveness, reliability, and support. Functionally all these control/automation systems, from a $150 DIY controller to the C4 controllers, work basically the same. They are all event based. A button is pushed, a light comes on. Time becomes sunset, a light goes on. The additional technical functions that C4 offers over DIY systems mostly relate to AV control/automation. There aren't many technical reasons to choose a different dealer system over C4.
My #1 piece of advice is to make your design as controller agnostic/independent as possible. Control4 makes some nice C4 branded stuff, but most of it requires a C4 controller. The home automation market is in a competitive phase. Lots of companies are entering the automation market. And C4 is a public company that is going through some business model changes that are adding yearly licensing fees. What happens if you find a reason to make a change of controller?